The present invention relates to an image forming apparatus.
A conventional image forming apparatus is disclosed in JP-A-2002-104694. The image forming apparatus has a housing, a sheet feed cassette, an image forming unit, a first width regulation mechanism, a reverse transport mechanism, and a second width regulation mechanism.
The sheet feed cassette has a sheet holding chamber for holding stacked sheets of paper, and can be housed within and drawn from the housing. The image forming unit is provided within the housing for forming images on sheets transported from the sheet holding chamber of the sheet feed cassette. The first width regulation mechanism is provided within the sheet holding chamber, movable with the center of an image formation range of the image forming unit as a reference position, and positioned according to the sheet width. The reverse transport mechanism is provided within the housing for turning over the sheet that has passed through the image forming unit and transporting the sheet to the image forming unit again. The second width regulation mechanism is provided within the reverse transport mechanism, movable in the width direction, and positioned according to the sheet width.
The first width regulation mechanism and the second width regulation mechanism are respectively independent, and their positions are separately changed by hand. Especially, the position of the second width regulation mechanism is changed by manually swinging a lever provided at the opposite side to the side of the housing at which the sheet feed cassette is housed.
In the conventional image forming apparatus having the above described configuration, the first width regulation mechanism regulates the position of the sheet in the width direction so that the sheet may be transported into the image formation range within the sheet holding chamber. Thereby, the image forming apparatus transports the sheet without displacement relative to the image formation range of the image forming unit and forms an image on the front side thereof. Then, the image forming apparatus ejects the sheet with the image formed on the front side from the housing to the outside, or transports the sheet to the reverse transport mechanism for image formation on the rear side.
Then, when the sheet is transported to the reverse transport mechanism, the sheet is turned over within the reverse transport mechanism, and further, the second width regulation mechanism regulates the position of the sheet in the width direction so that the sheet may be transported into the image formation range again. Thereby, the image forming apparatus transports the sheet without displacement relative to the image formation range of the image forming unit again and forms an image on the rear side thereof. Then, the image forming apparatus ejects the sheet with the images formed on both the front side and the rear side from the housing to the outside.
In this manner, the conventional image forming apparatus can form images only on the front side or both front and rear sides of a sheet.